日本国学是日本江户时代民间学术，不同于江户幕府倡导的日本朱子学与兰学。

在十七至十八世纪国学称古学，是在锁国中产生的思想，称古学与和学。这派代表性人物是荷田春满、贺茂真渊、本居宣长与平田笃胤，号为四大家。重点硏究古代日本的文学与神道，排除儒家与佛教影响。

「国学」一词与汉学、兰学相对，这一派以强调日本特点自诩。日后的尊王攘夷与明治时代国体论也与国学有关。

Kokugaku (Kyūjitai: 国学/Shinjitai: 国学; lit. National study) was an academic movement, a school of Japanese philology and philosophy originating during the Tokugawa period. Kokugaku scholars worked to refocus Japanese scholarship away from the then-dominant study of Chinese, Confucian, and Buddhist texts in favor of research into the early Japanese classics.